Chancellor John Healey has emphasised the economic arguments for a third runway at Heathrow, offering a more supportive assessment than prime minister Andy Burnham as the airport seeks political backing for its £33bn expansion. According to The Guardian Business, Heathrow has warned that uncertainty over the prime minister’s position could prompt investors to reconsider their commitment to the project.

Speaking in Bangkok, Healey said the government would examine submissions to a public consultation that had recently ended. He argued that Heathrow and other UK airports had made important contributions to employment and economic growth over recent decades, and presented expansion at Heathrow as a growth-led proposition. Healey, who voted for the third runway in the House of Commons in 2018, has described growth as the government’s foremost priority.

Burnham has not endorsed the scheme since entering Downing Street in July, instead indicating that the decision should rest with London and its residents. The Guardian Business cited a Sunday Times report suggesting that he had told transport secretary Heidi Alexander he remained unconvinced by the arguments for expansion. That stance contrasts with the approach of Healey’s predecessor, Rachel Reeves, who made approval of the runway a central element of her growth agenda last year.

Heathrow chief executive Thomas Woldbye said earlier this week that shareholders wanted to proceed but were concerned about the time the process was taking. While they had so far accepted the delays, he cautioned that their willingness to wait was not unlimited. The airport’s owners include Qatar’s investment authority, French private equity firm Ardian, Saudi Arabia’s Public Investment Fund and Singapore’s GIC. They are expected to decide in the coming months whether to seek formal planning permission.

Healey attended the International Monetary Fund’s annual meetings in Bangkok before returning to London to complete preparations for his 28 October budget. The Guardian Business reported that the IMF had praised Britain’s deficit-reduction efforts, with managing director Kristalina Georgieva encouraging him to maintain that approach. Official figures released on Thursday also showed that the UK economy had unexpectedly continued expanding in August.